Testate Amoebae in the 407-Million-Year-Old Rhynie Chert

Strullu‐Derrien, Christine; Kenrick, Paul; Góral, Tomasz; Knoll, Andrew H.

doi:10.1016/j.cub.2018.12.009

Cited by 21 publications

(19 citation statements)

References 48 publications

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“…The position of Palaeoleptochlamys hassii suggests a composition enriched in amine-containing fossilization products. Strullu-Derrien et al 23 pointed out an organic (non-agglutinated) composition for the test of this taxon and interpreted it as an arcellinid amoebozoan (testate amoeba). The ATR-FTIR results are consistent with an organic arcellinid affinity 46 .…”

Section: Resultsmentioning

confidence: 99%

“…1 and Supplementary Fig. 1) are located at the surface of polished thin sections and represent nine individual fossil cyanobacteria (Rhyniosarcina devonica 27 , Palaeolyngbya kerpii 28 , and a multiseriate Stigonema-like taxon), six unclassified arthropod cuticles, four unclassified plant spores, eleven plant cortices (Aglaophyton majus, Rhynia gwynne-vaughanii) and one set of rhizoids, four peronosporomycetes (Frankbaronia polyspora), two specimens of the amoebozoan Palaeoleptochlamys hassii 23 and ten fungi (six Palaeomyces sp. ; four glomeromycotan vesicles preserved within plants).…”

Section: Resultsmentioning

confidence: 99%

“…As such, they can be examined in transmitted light under an optical microscope, revealing exquisite, micron-scale, morphological detail. To date, almost all studies of the Rhynie chert biota have focused on the identification and systematic description of new taxa using this approach 21,23 . Chemical investigations have been limited but promising [24][25][26] .…”

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confidence: 99%

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Molecular fingerprints resolve affinities of Rhynie chert organic fossils

et al. 2023

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The affinities of extinct organisms are often difficult to resolve using morphological data alone. Chemical analysis of carbonaceous specimens can complement traditional approaches, but the search for taxon-specific signals in ancient, thermally altered organic matter is challenging and controversial, partly because suitable positive controls are lacking. Here, we show that non-destructive Fourier Transform Infrared Spectroscopy (FTIR) resolves in-situ molecular fingerprints in the famous 407 Ma Rhynie chert fossil assemblage of Aberdeenshire, Scotland, an important early terrestrial Lagerstätte. Remarkably, unsupervised clustering methods (principal components analysis and K-mean) separate the fossil spectra naturally into eukaryotes and prokaryotes (cyanobacteria). Additional multivariate statistics and machine-learning approaches also differentiate prokaryotes from eukaryotes, and discriminate eukaryotic tissue types, despite the overwhelming influence of silica. We find that these methods can clarify the affinities of morphologically ambiguous taxa; in the Rhynie chert for example, we show that the problematic “nematophytes” have a plant-like composition. Overall, we demonstrate that the famously exquisite preservation of cells, tissues and organisms in the Rhynie chert accompanies similarly impressive preservation of molecular information. These results provide a compelling positive control that validates the use of infrared spectroscopy to investigate the affinity of organic fossils in chert.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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Molecular fingerprints resolve affinities of Rhynie chert organic fossils

et al. 2023

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“…The interactions between Mucoromycota and their bacterial endosymbionts are an ancient phenomenon dating back as far as 400 million years ( 57 ). Flowering land plants such as rice developed far later (134 million years ago) than protozoan and metazoan predators such as amoebae and nematodes (400 million years ago) ( 58 , 59 ). Thus, the establishment of a mutualistic interaction between Rhizopus and rhizoxin-producing Mycetohabitans ( 60 ) may have allowed the fungal host to evade predator attack, thereby gaining an evolutionary advantage over aposymbiotic or rhizoxin-negative symbiotic fungi.…”

Section: Discussionmentioning

confidence: 99%

Toxin-Producing Endosymbionts Shield Pathogenic Fungus against Micropredators

Hertweck

Radosa

Cseresnyés

et al. 2022

mBio

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“…The interactions between Mucoromycota and their bacterial endosymbionts are an ancient phenomenon dating back as far as 400 million years (Mondo et al, 2012). Flowering land plants like rice developed far later (134 million years ago) than protozoan and metazoan predators such as amoebae and nematodes (400 million years ago) (Poinar, 2011; Strullu-Derrien et al, 2019). Thus, the establishment of a mutualistic interaction between Rhizopus and rhizoxin-producing Mycetohabitans (Lastovetsky et al, 2016) may have allowed the fungal host to evade predator attack thereby gaining an evolutionary advantage over aposymbiotic or rhizoxin-negative symbiotic fungi.…”

Section: Discussionmentioning

confidence: 99%

Toxin-producing endosymbionts shield pathogenic fungus against micropredators

Richer

Radosa

Cseresnyés

et al. 2022

Preprint

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The phytopathogenic fungus Rhizopus microsporus harbours a bacterial endosymbiont (Mycetohabitans rhizoxinica) for the production of the toxin rhizoxin, the causative agent of rice seedling blight. This toxinogenic bacterial-fungal alliance is, however, not restricted to the plant disease, but has been detected in numerous environmental isolates from geographically distinct sites covering all five continents. Yet, the ecological role of rhizoxin beyond rice seedling blight has been unknown. Here we show that rhizoxin serves the fungal host in fending off protozoan and metazoan predators. Fluorescence microscopy and co-culture experiments with the fungivorous amoeba Protostelium aurantium revealed that ingestion of R. microsporus spores is toxic to P. aurantium. This amoebicidal effect is caused by the bacterial rhizoxin congener rhizoxin S2, which is also lethal towards the model nematode Caenorhabditis elegans. By combining stereomicroscopy, automated image analyses, and quantification of nematode movement we show that the fungivorous nematode Aphelenchus avenae actively feeds on R. microsporus that is lacking endosymbionts, while worms co-incubated with symbiotic R. microsporus are significantly less lively. This work uncovers an unexpected ecological role of rhizoxin as shield against micropredators. This finding suggests that predators may function an evolutionary driving force to maintain toxin-producing endosymbionts in non-pathogenic fungi.

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Testate Amoebae in the 407-Million-Year-Old Rhynie Chert

Cited by 21 publications

References 48 publications

Molecular fingerprints resolve affinities of Rhynie chert organic fossils

Molecular fingerprints resolve affinities of Rhynie chert organic fossils

Toxin-Producing Endosymbionts Shield Pathogenic Fungus against Micropredators

Toxin-producing endosymbionts shield pathogenic fungus against micropredators

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